Transmission control system



Jan. 6, 1953 1 B; FORMAN TRANSMISSION CONTROL. SYSTEM Filed July 24,1951 Patented Jan. 6, 1953 UNITED STATES 2,624,207 'rnANsMTssroNooN'raoL SYSTEM Louis B. Forman,

Chrysler Corporation, corporation of Delaware Detroit, Mich., assignorto Highland Park, Mich., a

Application July 24, 1951, Serial No. 238,300

9 Claims. (Cl. 'i4-472) This invention relates to motor vehicles andrefers more particularly to power transmissions and control systemstherefor.

My invention has particular reference to transmission control systemswherein the disengagement ofY positively engageable drive controlelements, is facilitated by relieving the torque load on these elementsas by momentary interruption of the engine ignition system. Examples oftransmissions `of this character are described in thevpatents to Carl A.Neracher et al. 2,455,943, granted December 14, 1948, and Augustin J.Syrovy et al. 2,490,604,granted December 6, 1949,

Itl has been customary, as shown by the aforesaid patents, to provide ashiftable drive control element of toothed character' arranged tointerengage with a second toothed drive control element after passingthrough a toothed blocker.

Engagement occurs upon synchronism obtaining between the drive controlelements subsequent to engine deceleration by accelerator releasingmovement, and the shiftable element is adapted to be unloaded, asdescribed above, to facilitate its disengagement from its companiondrive control element.

The drive control elements are generally so arranged in the transmissionthat upon relative engagement under governor control at or above apredetermined vehicle speed, there is provided a fast speed ratio drivethrough the transmission, usually a direct drive, and when relativelydisengaged under governor control below a predetermined speed, or bykickdown means such as accelerator actuated switch means overruling thegovernor, there is provided another speed ratio drive which is usually aslower speed ratio drive than the first mentioned one.

Also customarily provided are prime mover or differential pressureservomotor means which may comprise a -spring and a hydraulic or vacuumoperated motor having a movable piston, for controlling shift of theshiftable drive control element through an associated shift rail orlever system. In the case of the hydraulic system, as typii'led by theSyrovy et al. patent aforesaid, pressure iiuid acting upon the pistonwill cause it to compress a disengaging spring and an en gaging spring,and build up suicient available force in the latter to move the shiftrail and by it the shiftable drive control element against its blockerand then into engagement with its companion drive control element whensynchronization of the drive control elements subsequently occurs.

In the case of the vacuum power system, as

typified oy the Neracher et al. patent, vacuum is utilized to cause thepiston to compress a disengaging spring and through a rod extension ofthe piston., unload an engaging spring previously tensioned by operationof the rod, the latter spring in turn acting upon a lever to eiectmovement of the shiftable element against its blocker and intosubsequent engagement with its cornpanion drive control element when thedrive control elements obtain synchronism.

Transmission systems of the aforesaid typical character also usuallyinclude electromagnetically controlled valving for controlling venting(admission of atmospheric pressure) of the servomotor and operation ofthe piston such that when the motor is vented, the disengaging springactuates the piston to effect disengaging shift of the shiftable drivecontrol element accompanied by ignition interruption, the latteroccurring as an incident to available lost motion operation of thepiston relative to the shift rail in Syrovy et al., and the `piston rodrelative to the lever operating member in Neracher et al. l

Customarily there is also provided an ignition interrupter switchoperated by movement of the piston in Syrovy et al. or by the piston rodin Neracher et al. Moreover, as in the above patents, there is providedan electrical system intended to accommodate interruption of theenginerignition only during the disengaging stroke of the piston, itbeing so arranged that even though the ignition interruption switchcloses on the return (engaging) stroke, the ignition is not ordinarilygrounded out Ibecause at such time neither of the parallel arrangedkickdown and governor switches which are arranged in series with theignition interrupter switch and in series with the valve solenoid in aparallel circuiting is closed. Hence firing of the engine is not usuallyinterrupted during acceleration from vehicle standstill in the slowerspeed ratio drive.

As improvements upon the Neracher et al. system of control,` it has alsobeen suggested, as shown in the patents to Albert E. Kimberly, Jr.2,427,408, granted September 16, 1947, and Victor E. Matulaitis2,29l,l89, granted July 28, 1942, to arrange the governor and kickdown`switches in series with a ground and the valve solenoid and to providea separate circuit for the ignition interruption control that includesthe interruptor switch and means such as an additional switch ormechanical control means intended to render the ignition interrupterswitch although actuated, operative to interrupt the ignition in onlyone direction of movement of the piston rod, whereas in Neracher et al.and Syrovy et al. aforesaid,

the ignition interrupter switch is arranged in series with parallelcuits.

Although the foregoing described arrangements have in general beensatisfactory; they have been open to one or more unforseen conditions ofoperation which it is desirable to avoid in order to provide a foolproofsystem. Thus in certain of the prior systems it has been possible toobtain ignition interruption while the transmission was in its lowergear,l i. e., when the shiftable drive control element is disengaged,but at a time when the vehicle speed was such as to require the governorto call for an upshift. Under these conditions the shiftable drivecontrol element moves against its blocker but obviously cannot engageuntil the relative speeds of the engageable drive control elements aresynchronized by deceleration of the engine through accelerator releasingmovement. Hence, should the operator instead of releasing theaccelerator, accidentally or deliberately depress the accelerator towide open throttle position in demanding further acceleration from thetransmission (thus closing the kickdown switch) ignition interruptioncould occur because the kickdown operation would also yvent theservomotor to allow the piston to recede and operate the ignitioninterrupter switch and even though the shiftable drive control elementwas not engaged.

This condition has also been found to occur under similar conditionswhen closing, opening and re-closing of the kickdown switch occurs dueto unsteady pedal pressure or because of relative motion between theengine and throttle linkage.

Furthermore, in the arrangement disclosed by Neracher et al. and Syrovyet al., especially where a higher resistor type of ignition harness hasbeen employed, some lurching of the vehicle has been noticeable invehicle operation during upshifts. It is believed that in a circuitingwherein actuation of the interrupter switch places the ignition primarycoil and the solenoid of the control valve in parallel circuits, thesolenoid coil acts as a parallel impedance of low value to the primarycoil of the ignition and causes the spark delivered by the secondary atthe plugs at the time of current flow thereto to be weakened. In thisconnection, it may be observed that under normal engine operation thehigher the engine R. P. M., the lower is the secondary voltage, andsince the upshift takes place at a substantial t. P. M. the effect ofthe low impedance is to weaken the spark sufciently so that it may beunable to keep the engine running momentarily, as by causing the engineto misre. This condition can occur, for example, in the Neracher et al.arrangement and inthe Syrovy et al. system when the relay coil of thelatter has a-low impedance effect on the ignition primary. Y

An object of my invention is to provide a improved ignition interruptioncontrol adapted for use, for example, with a transmission control systemof the types disclosed in the aforesaid patents and which is capable ofoperation without accommodating actual ignition interruption or misfringof the engine during the return i. e., upshift stroke of the piston, andwhich will positively, so far as now known, limit ignition interruptionto only such occasions when it is intended to facilitate relativedisengagement of the drive control elements.

Another object is to pro-Vide a transmission shift control system havingmeans for interruptgovernor and kickdown ciring the engine ignition wheneifecting disengagement of interengaged drive control elements but whichsystem incorporates means associated with the motion transmitting meansfor the disengageable drive control element for preventing ignitioninterruption when the drive control elements are Ilot engaged.

It is also an object of the invention to provide a transmission drivecontrol system having means for interrupting the engine ignition wheneffecting a downshift and which includes means for preventing saidinterruption of the engine ignition by a driver initiated downshiftoperation in a vehicle speed range in which an upshift operation hasbeen previously initiated, but not completed to the point of effectingengagement of the drive control elements.

Still another object of the invention is to provide a transmission shiftcontrol system having means for interrupting the engine ignition wheneffecting a downshift, but which system inhibits weakening of theignition spark intensity during the upshifting operations.

Still another object is to provide a transmission shift control systemhaving means for interrupting the engine ignition when effectingdisengagement of the drive control elements, but which system providessafeguards both against weakening of the ignition spark intensity duringupshifting and against ignition interruption when a driver downshiftoperation is initiated in a vehicle speed range accommodating an upshiftbut which upshift has not been completed.

A specific object of the invention is to provide a transmission controlsystem having means including an ignition interrupting switch forinterrupting the engine ignition when effecting disengagement ofinterengaged drive control elements, one of which elements is ashiftable element, which interruption means includes a control switchand operating means therefor on the motion transmitting means for theshiftable element for preventing ignition interruption during engagingoperations of the shiftable element and during a kickdown operationinitiated when the shiftable element is not engaged but is against itsblocker.

Other objects and features of my invention will be apparent from thefollowing description wherein:

Figure 1 is a diagrammatic plan view of the driving power plant for thevehicle;

Figure 2 is an elevational view partly inV section of my invention asapplied to a semi-automatic four speed forward and reverse transmission,a part of the control system being schematically illustrated, themanually operable clutch sleeve being shown in its forward or high rangeposition for starting the Vvehicle from rest, and the power shiftablemechanism and power operable clutch sleeve being shown Ain the releasedposition of the latter; and

Figure 3 is an elevational view similar to a portion of that in Figure 2and showing the power shiftable clutch sleeve in its direct drive orengaged position and the power shifting mechanism in the correspondingposition. Y

In the drawings in which similar numerals indicate similar parts of thestructure, Figure l illustrates a typical motor vehicle power planthaving a conventional engine A for transmitting power through apropeller shaft I0 to drive the rear ground wheels H. In the housing Bthere may be provided a iiuid power transmitting device, such as a fluidcoupling arranged in tandem acca-sor with-a master frictionv clutch ofknowntype`,the latter being releas'able to' uncouple the engine from thetransmission by operation of a conventional clutch pedal I2. Rearwardlyof the housing B is a transmission C which may be any type incorporatingpositively engageable drive control elementsV of a character usuallyvsubject to substantial thrust or torque load in operation, the latterconditions making the use of some formv of unloading means desirable toinsure'release of the drive control elements when a speed changerequiring disengagement of these elements is necessary.

The transmission C maybe of various known types. For purposes ofillustration I have shown in Figure 2, a commercial form of four-speedand reverser countershaft' underdrive transmission.

This transmission comprises anvinput or driving shaft I3 which receivesdrive from the engine A by way of the clutch assembly B, and an outputor'driven shaft I4l which is adapted to transmit drive tothe propellershaft IIB. The driving shaft I3 carries the main driving gear or pinionI5 and a set of positive jaw clutch teeth I which are adapted to beengaged by the teeth of a jaw clutch sleeve D. Aswill be hereinafterseen, the sleeve D together with the clutch teeth vIES compriserelatively movable drive control elements for effecting stepup andstepdown manipulation of the transmission.

The clutch sleeve D is slidably splined on teeth, not shown, of aforward hub portion of the high or third speed gear 22 which isrotatably journalled von the driven shaft I4 and adapted to be clutchedthereto through a jaw clutch sleeve F slidably splined on a hub, notAshown, drivin'gly carried by the shaft Il! and interengageable with jawclutch teeth carried by the gear 22. The forward shift of sleeve D forclutching with teeth I3 isnormally controlled or impeded by a toothedblocker E whereby clutching is limited to synchronous relationship inthe speeds of rotation of gears I5 and 22 and, in the particularconstruction illustrated, limited to 'engine coast conditions obtainableby accelerator releasing movement to secure deceleration of the engine.The blocker E is journalled on a .conical surface, not shown, carried bythe shaft I3 against which it is frictionally urged by a spring, alsonot shown, and has a limited lost motion connection with the sleeve D orgear 22l whereby it may rotate to place its teeth in blocking relationto the teeth of sleeve D whenever the gear I5 rotatably leads or lagsthe sleeve D. When sleeve D moves past the blocker E into engagementwith the clutch teeth I6, the gears I5 and 22 are placed ina twowaydirect drive relationship.

Gear 22, as stated above, is loosely journalled on the driven shaft I4whereas the pinion I5 is part of the inputv shaft I3. Also looselyjournalled on the output shaft I4 .is a-lowor first speed gear 21 havingjaw clutch teeth 28 engageable Aby the sleeve F. `Associated withthesleeve F- on each side thereof is any commercial typeof blockersynchronizers 23 such thatclutch F may be-shi-fted from a neutralposition disengaged from teeth 25 vand 25 forwardly to a high'rangeposition to synchronously clutch shaft I4 with the high speed gear 22through the teeth 2-5 or rearwardly -to a low range position tosynchronously clutch shaft I4 with the low speed gear 21 at its teeth2S. Manual shifts of the sleeve F are facilitated by release of the mainclutch at l5VA by means of the clutch pedal I2.

Gear 22 is also adapted to be driven from gear I5 aty ra. speeddifiercntfrom 1:1 and to this 'end I havesho'wn a countershaft type one-wayreduction driving means betweenthese gears. This drive comprises thecoaxially rotatable countershaft gear 30 and cluster gear 3| wheels 32,33 respectively, in constant mesh with gears I5, 22, and 21 and anoverrunning roller clutch G operably interposed therein between the gear30 and cluster 3 I. A stationarily mounted countershaft 34 provides ajournal support for the countershaft gears. Assuming the usual clockwiserotation of shaft I3 as viewed when looking from front to rear of Figure2, then overrunning clutch G `willautoma'tically clutch gear 30 andcluster 3i together when gear 33 is driven counterclockwise `at a speedtending to exceed that of the cluster 3| and automatically release thedrive between these gears to allow gear 30 to slow down below the speedof cluster 3l. For obtaining reverse drive an idler gear (not shown)having constant Vmesh vwith the gear 33 is shiftable rearwardly intomesh with a gear 35 xed on shaft I4, the clutch F being then in itsneutral posi-- tion disengaged from teeth 2S and 28.

Asv thus far described, it will be apparent that with theiparts arrangedas in Figure 2, sleeve F being then lin high range position engaged withteeth 26, drive of shaft I3 will cause the output shaft I4 to be drivenat a reduction drive (third speed) through thev gears I5, 30 overrunningclutchG, gears 32, 22 and sleeve F. Should the sleeve D be biasedforwardly during this reduction drive, blocker E will obstruct sleeve Din an intermediate position of its shift preventing ratch'eting of itsteeth with thev teeth I3. However, if the driver releases the enginethrottle control in the form of the usual accelerator pedal then, aswill be apparent, overrunning clutch G will'allow gear I5 and teeth I6to slow down relative to the sustained speed of gear 22 and when thespeed of gear I5 reaches synchronism with that of gear 22, blocker Ewill move to an unblocking position and allow sleeve D to move furtherforwardly `to clutch its teeth with teeth IB to the position shown inFigure 3, to provide the direct -drive (fourth speed), clutch Gcontinuing its overrunning operation. Upon return of sleeve D todisengaged position shown in Figure 2, followe'dy by speeding up theengine, overrunning clutch G will automatically engage to restore thereduction drive.

When clutch sleeve F is shifted rearwardly to low range position toclutch gear 2'! to shaft I4 an overrunning slow speed drive (firstspeed) is transmitted vfrom the shaft I3 to the shaft VIll by way'of thegears I5, 35, overrunning clutch G, gears 3:3 and 21 and sleeve F. Atsuch time as the sleeve D is biased forwardly and the shaft I3 isallowe'dfto slow down to permit the teeth I5 to become synchronized withthe sleeve D, the vsleeve will move' past the blocker E and clutch withthe teeth I5 'to' establish a two-way relatively fast speed Vdrive(second speed) in the low range, which drive will be from the shaft I3through the sleeve D, gears 22 and 32, gears 33 and 21, and clutch F tothe shaft I4', the `clutch G overrunning by reason of the cluster SIrotating at a higher speed forwardly than the gear`33.

It will be understood the driver may start the Yvehicle from rest in thelow range drive and subsequently shift to theV high range incident tomomentary release of the master clutch and lthis either prior to orsubsequent to engagement of the clutch D. Most drivers, however, usuallystart the vehicle from rest in the slow speed ratio of the high rangeand at a subsequent Ahigher speed obtain the automatic upshift to directdrive by momentary release of the accelerator pedal described above.

A more complete description of the transmission specifically illustratedin this application and its method of operation is set forth in thepatent to A. J. Syrovy et al. 2,490,604 aforesaid.

A speed responsive governor means O is provided to control forward biasof the sleeve D as well as rearward bias thereof as will be presentlymore apparent. Moreover, during drive in either second or fourth speedsreferred to above, a downshift to first or third speeds respectively maybe effected by way of overruling the governor O through driverdepression of the accelerator pedal M to substantially wide openthrottle position, which operation is referred to in greater detailbelow.

As seen in Figure 2, I have illustrated a servomotor H by which toobtain power actuation of the clutch sleeve D, the motor hereillustrated being of the pressure differential and spring operated typeand in the disclosed embodiment functioning by means of fluid pressure.This motor preferably comprises a cylinder 36 slidably receiving apiston 31. The piston slidably receives a shift rail or rod 38 mountedto operate in the guideways 39 and 46. Fixed to rod 38 is a yoke 4 I, ahub portion 42 of which is secured to the rod 38 by means of a dowelscrew 43. The rod 38 and yoke 4I constitute motion transmitting means Sfor the sleeve D, the yoke 4| as seen in Figure 2, having fingers 44engaging in a Y groove 45 o-f the sleeve D to effect shift thereof.

A relatively small preloaded engaging spring 46 surrounds the rod 38 andis disposed between the hub of piston 31 and the hub 42 of the yoke 4I.This spring 46 provides a lost motion thrust transmitting connectionbetween the piston 3'! and the hub 42 of the motion transmitting means Ssuch that the piston 31 may be moved forwardly (to the left in Figure 2)for its power stroke, the piston 31 continuing its forward motion byfluid pressure even after the clutch D has been moved against theblocker E until the lip 41 of the piston uncovers the relief port 48 ofthe cylinder 36 whereupon forward movement of the piston 31 will cease,the fluid pressure being then expended through the relief port 48.

During the said forward movement of the piston 31 the engaging spring 46is compressed and urges the rail 38 through the hub 42 of the yoke 4Iforwardly thus in turn shifting the clutch sleeve D to its intermediateposition blocked by the blocker E. Subsequently upon synchronousrotation of the teeth I6 and sleeve D being obtained in response toaccelerator releasing movement, the sleeve D is moved through theblocker E into engagement with the teeth I6 of the drive pinion I5,which is its fully engaged upshifted position shown in Figure 3,establishing the previously described direct drive between the shaft I3and gear 22.

A relatively large preloaded downshift or kickdo-wn spring' 49 isdisposed between an abutment ring 50, located at the forward end of thecylinder 36, land the piston 31. This spring serves to return the piston3'! and sleeve D from their Figure 3 positions to their downshifted ordisengaged position shown in Figure 2. It will be observed from Figure 3that the piston 31 when in its furthest forward position shown in thisfigure uncovering the port 48 has moved further than the shift rail 38such. that a gap 5I is created between the piston 31 and a shoulder 52of the portion 53 of the shift rail. This gap 5I facilitates a lostmotion movement of the piston 31 relative to the shift rail 38 prior todisengaging movement of the sleeve D which can only commence followingabutment of the piston 31 with the shoulder 52.. As previously noted,forward movement of the piston 31 is stopped upon uncovering the port48, the latter permitting any excess pressure required to hold thepiston 31 in its furthest position to be relieved and preventing fthebuilding up of such excess pressure in the cylinder.

The pressure fluid supply system is shown in Figure 2 and comprises asuitable supply source 60, vWhich is usually the transmission sump. Apump Q of the rotary gear type is mounted on the shaft I4 and has itsrotor 6I driven by that shaft, oil being drawn from the supply source 60through the conduit 62 to the pump inlet 63 and is delivered underpressure at the pump outlet 64 to the conduit 65 and then to the passage66 under control of a ball valve K. A relief valve, generally designatedby the numeral 61 and provided at the pressure side of the pump betweenthe outlet 64 and the ball valve K serves as a relief valve in the eventthe valve K is not open in normal operation of the transmission tothereby permit pressure fluid trapped behind the piston 31 to be dumpedback into the transmission sump 60 through the conduit 61a.

When the valve K is closed, oil under pressure is forced directly fromthe pump through the passage 66 to the cylinder 36 where it moves thepiston 31 forwardly to eiect forward movement of the shift rail 38 inthe manner described above whereby the Shift sleeve D is operated fromits disengaged position in Figure 2 to its engaged position of Figure 3to establish second or fourth speed ratio drive depending upon whetherthe clutch F is engaged with the rst speed gear 21 or with the thirdspeed gear 22.

Valve K is closed by bias of a valve spring 68 'acting against a ball 69to close a discharge port 1I) opening into a passage 1I draining to thesump or supply source 63. The valve K is actuated to its open positionunder control of an electromagnetic device comprising a solenoid Lhaving a plunger 12 connected with the movable core of the solenoid. Thevalve K is closed when the solenoid L is deenergized. The spring 68 thenactuates the ball 69 against a seat 13 to close the port 10 and effectsmovement of the solenoid plunger 12 to its retracted position. The valveK is open when the solenoid L is energized, the solenoid core thenmoving the plunger 12 downwardly to push the ball 69 olf the seat 13 Yofport 10. The oil may now flow from the pumpQ throughthe conduit 65, port10, passage 1I, back to the sump 60.

When the valve K is open, it is impossible for suilicient fluid pressureto develop in the passage 66 to move the'piston 31 against the forceexerted by thepiston return spring 49 which then maintains the piston atthe extreme rearward position of its capable movement. Hence the piston31 is actuated by fluid pressure only to establish second and fourthspeeds respectively at which time the valve K is closed and the solenoidL deenergized. Figure 2 shows the valve K in its open position and thepiston 31 in its position retracted by spring 49, and Figure 3 shows thevalve K in its closed position and the piston 31 in its furthest forwardposition under control of the pressure fluid.

VEnergiration and deenergization of the solenoid 9. L is brought aboutby operation from one DOsition to another of either of two controlmembers, one actuated in response to vehicle speed, and the other inresponse to manipulation by a driver control member. One of thesecontrol members is the governor O, and the other is a kickdown switchgenerally designated by the letter P. Suitable electrical circuit meansare provided for eifectuating the control operation of the governor andkickdown switch overthe solenoid L. Thus a suitable source of electricalenergy, for example, a storage battery 15 has one side grounded as at 16by a conductor 11 and its other side con.. nected by a conductor 18through an ammeter 19 to the ignition switch 80. A conductor 8| connectsthe ignition switch with one terminal 'S2 of the solenoid L, the otherterminal v83 of the solenoid being connected by a conductor 84 with aterminal 85 of a switch generally designated by the letter N which isoperated by the governor O and which has a second terminal 81 connectedto a ground 8S by a conductor 89. From the governor switch terminal 85 aconductor 99 eX- tends to a terminal 9| of the kickdown snap switch P,this switch having a second terminal 92 connected to a ground 93 by aconductor 94.

The governor switch N is closed by a movable conductor switch bar 95operated by an insulated sliding sleeve 96 'of the governor O, theswitch being closed when the bar 95 bridges the terminals 85 and 8.1.The kickdown switch l?l is of the snap type and has a conductor bar 91which closes the same by bridging the terminals `9| and 92 of thisswitch.

Thus by means of the governor switch N and the kickdown switch P, twoparallel ground circuits are provided for the solenoid YL, the governorswitch N opening at a speed proportional to vehicle speed established bythe drive connection |99, ||l| between the governor O and thecountershaft cluster 3|. It will be understood that the governor drivingmeans |El| Vmay if desired be on the driven shaft I4.

The kickdown switch P, as shown in Figure 2, is in open position undercontrol of a coil spring m2 and which biases the accelerator M to itsreleased position.

The accelerator M is suitably connected `with the usual enginecarburetor throttle valve by means including linkage |133', Ille whichserves to open and close,- the throttle valve. Interposed in thethrottle valve operating linkage vis a. lever |95 pivotally supported at|86 and having spaced fingers or projections |08, |||l for operating theactuating iinger ||2 of the `snap switch?. The mechanism is preferablyarranged such that in operation, the switch iinger -||2 is engaged bythe lever projection |98 as the throttle valve in response to depressionof the accelerator M .approaches its full open throttle position, so.that the switch Pis closed with snap action dur-ing approximately thelast ov or so of throttle ohlng movement. It will be understood that theopera.. tion of this switch may be adjusted to occur subsequent to fullopen throttle position by the provision of suitable lost motionmechanism such as disclosed in the patent to Neracher et al.r2,l55,94l3. When the accelerator M is released, the finger It comesinto contact with the actuating ringer I2 of the switch near the Vfullyreleased position of the accelerator to actuate the switch P to its openposition, again `by snap action, the parts being-so arranged that theswitch P will be opened by finger |||l whenever the accelerator pedal is.Eully released.

'by the letter J, is of Grounding of the ignition is provided by a circuit including a conventional normally open interruption switch T whoseoperating ball |25 projects into the cylinder 35 and is operated by cams|26 and |21 of the piston 31 in its movement between clutch engaging anddisengaging positions, as will hereinafter be explained.

As noted above, by prior control circuits and structures, it waspossible to cause ignition interruption to occur when not desired,during an uncompleted upshift, through accidental or deliberateoperation of the kickdown switch P by the operator acting upon theaccelerator M, and insystems providing a common ground for the ignitionprimary winding and the solenoid I.. `in parallel arranged circuits, litwas possible for the solenoid `L to act as a parallel impedance of lowvalue to the primary coil |23 to weaken the spark delivered by thesecondary coil |24 at the sparkplugs |29 when current flow thereto tool;place.

A feature of the present invention is to overcome these difficulties. Inorder to accomplish this I preferably provide in the ignition groundingcircuit a second, normally closed, interruption control switch Y mountedon the transmission casing wall |3| forwardly of the motor H. The springbiased plunger |32 of the switch Y projects inwardly of the casing andis adapted to be actuated by a cam headed radial abutment or projectionmember |33 mounted on the, motion transmitting means S, and preferablythreadably received in the hub 42 of the clutch ,sleeve yoke Al andradially adjustable thereon in relation to the switch plunger |32. Thehead of the switch actuating member is of suilcient width to effectoperation of the switch from a normally closed position when the clutchsleeve D is engaged to its open position when the sleeve vD isdisengaged, the switch being maintained in open position during allpositions of the sleeve between its `fully retracted (disengaged)position and its blocked position, and operation oi the switch toestablish its closed position commenc ing with movement of the sleeve Dthrough the blocker E.

Conductors |34, |35, |35 connect the primary winding |23 with theterminal |31 o the switch Y whose second terminal |38 is connected by aconductor |39 with terminal |45) of the switch T whose second terminal|42 is connected by a conductor |44 with the terminal 85 of the switch Noperated by the governor O which, when closed, provides a ground 88 orby the conductors |44 and 9d with the kickdown switch P which, whenclosed, provides a ground 93.

The operation of the transmission and control system will now bedescribed. Let it be assumed that the vehicle is at a stand-still, withthe manual sleeve F shifted forwardly in engagement with the teeth 26 ofthe third speed gear 22, as seen in Figure 2. At this time the governorswitch N will be closed and provides a circuit from the battery 15 toground 88 by way of the conductors 8| and 84 and solenoid L, thusenergizing the latter whereby the solenoid rod 12 maintains the bal1 69of the valve K in its down position venting the motor H so that spring49 holds the clutch sleeve D in the position shown in this figure. Theinterrupter switch T is open, as shown,

the'ball operator 25 being free of the lip 41 of the piston 31 and theinterrupter switch control switch Y being closed since in the positionshown the operating member E32 of this switch is held in raised positionclosing the switch by the abutment member |33 of the shift yoke 4| forthe sleeve D. The kickdown switch P is open since the accelerator pedalM is in released position.

By depressing the accelerato-r pedal the vehicle is driven in thirdspeed ratio drive and at some predetermined speed of vehicle travel, forexample, 12Yto 14 M. P. H. (6 to '7 M. P. H. in rst speed) the governorO actuates the switch N to open position. This action deenergizes thesclenoid L and the valve K is thereupon closed by operation of thespring 68 which moves the ball 69 to close the port 1Q at the entranceof the return passage 1|, thus permitting pressure to be built up by thepump Q in the passage 56.

When the fluid pressure builds up sumciently, the piston 31 movesforwardly for its upshift stroke and comes Ito rest at the positionsho-wn in Figure 3 where the relief port 48 is uncovered to relieve thefluid pressure and maintain the piston at this position. The forwardmovement of the piston 31 is utilized in compressing the springs 6 and49. Initially the spring 46 moves the sleeve D through the yoke 4| ofthe motion transmitting means S to its blocked position against theblocker E, these parts thereupon coming to a temporary rest. Then lostmo-tion movement occurs between the piston 31 and the means S duringwhich the springs 46 and 49 continue to compress until the pistonuncovers the relief port 48, as seen in Figure 3.

During this forward movement of the motion transmitting means S and thepiston 31 of the switch Y is held open by the abutment member |33 andthe switch K is first closed by the cam |26 of the piston and heldclosed momentarily by the lip 41 and then permitted to reopen by the cam|21.

There is nc grounding of the ignition since both switches N and Y areopen.

Thereafter upon accelerator release, to synchronize the speeds of thesleeve D and the clutch teeth I3, the sleeve D is moved by spring 46acting upon the yoke 4| of the mo-tion transmitting means S, to itsengaged position seen in Figure 3, the rail or rod 38 moving with theyoke 4| to the position shown in this figure. The transmission is nowestablished in fourth speed.

During movement of the sleeve D through the blocker E, the yoke abutmentmember |32 begins to move away from the operating plunger |32 of theswitch Y and the switch is in its normally closed position 'by the timethe teeth of the clutch sleeve D enter 'into engagement with the clutchteeth lil.

It is to be noted that because the switch Y is maintained open until thesleeve D enters the teeth IE5 should the operator either accidentally ordeliberately depress the accelerator pedal M to full open position ofthe throttle at a time when the governor switch N is open and the sleeveD is against the blocker E the switch P will be closed and solenoid Lenergized to vent the motor H permitting the pis-ton 31 to momentarilyclose the normally open switch T in its rearward movement, but theignition coil |23 will not lbe grounded because during this entireoperation the switch Y which is in series with the switch T and coil |23is in open position. Moreover, it will be noted that by reason of theswitch Y closing only when the sleeve D enters into engagement withteeth l5 and the switch is momentarily closed and again reopened priorto closing of switch Y, during the upshift operation, no weakening ofthe ignition can occur in the manner described above because it isimpossible to provide a common ground for the ignition primary coil |23and the solenoid L! Once the clutch sleeve D is established in fourthspeed, a downshift to third speed is eifected either by manually closingthe kickdown switch P through depression of the accelerator tosubstantially full open position of the throttle or by Ithe automaticclosing of the governor switch N when the speed of the vehicle dropsbelow the upshift speed set for the transmission.

For example, when the driver desires to manually effect the downshiftfrom fourth speed he may fully depress the accelerator M. During thisoperation the switch P is closed. Since at this time the engine isdelivering its full power, it is desirable to eifect torque relief atthe teeth I6 to facilitate the release of sleeve D for the downshift.Moreover, at this time the switch Y is in its Figure 3 closed position.Hence when the switch P is closed, ground 8S is applied to the solenoidL circuit from the battery 15 causing energize/tion of the solenoid andopening of the valve K to vent the motor H. Venting of the motor. Hpermits return movement of the piston 31 to start under urging of thespring 49, it taking up the gapv 5| previously established during lostmotion movement between the piston 31 and rail 38 and coming to restagainst the shoulder 52 of the rail 38. During this movement the pistoncam |21 acts on the ball 25 of switch T to close this switch and the lip41 keeps the switch T momentarily closed.

Until the switch T is closed the sleeve D usually remains engaged withthe clutch teeth I6 by reason of the torque on its teeth, and the switchY is therefore closed. Hence when the switch T is closed by the piston31, the switches Y and P being then also closed, a ground cir-cuit isestablished between the primary coil V| 23 and ground 93 of the switchP, grounding the ignition. The engine now missing re, unloads the torqueon the teeth of clutch |6 and the teeth of the sleeve D and permitsdisengagement of the sleeve D, whereupon the piston 31 completes itsrearward or return stroke back to the position illustrated in Figure v2together with the rail 38 and the abutment member |33 again engages theplunger |32 of the switch Y as seen in Figure 1 to again hold thisswitch open.

It will be understood that the ignition is restored to normal operationas soon as the cam |26 of the piston leaves the ball |25 of the switch Tpermitting the latter to be restored to open position.

When the accelerator M is later releasedsufciently to open switch P,fourthspeed may be again restored as previously described, provided thevehicle speed is still such that the governor switch N is open.

For automatic downshift from fourth to third speed under control ofthevehicle governor O, it is only necessary to reduce the vehicle speed toor below the speed at which the governor switch N normally closes. Suchaction effects closing `of switch N and establishment of a circuitbetween battery 15 and ground 88 through the solenoid L which is thenenergized. The motor H is now vented as described above with respect todownshift by kickdown operation and the ,at Said Ashiftable switches *i*and Y are' .operated as there 'described.

When the sleeve F is in its rearward or low range position, then upshiftand downshift movement of sleeve D will be the same as that set forthfor operation of `this sleeve in the high range setting. However, sincethe governor O is driven from the countershaft as at IBI in Figure 2,the governor O will function at a somewhat lower car speed depending onthe gear ratios for first and second as compared with third and fourthas will be readily understood.

From the foregoing description of my invention, it will be apparent thatI have provided a novel and foolproof ignition interrupter controlsystem and structure for transmissionshaving both governor and manuallycontrolleddownshifting wherein ignition interruption fordisengagingengaged clutch elements is initiated at required times only.

It will also be appar-ent that the invention is applicable to otherforms of transmissions. Moreover, although the disclosed embodiment ofthe invention is well adapted for carrying out the objects hereinaboveSet forth, it will be understood that various modifications, changes,and substitutions coming within the spirit of my invention and withinthe scope of the appended claims are also contemplated.

What is claimed is:

Vl. I Il a Power transmission for driving a vehicle having `an engineprovided with an ignition system; a shiftable transmission drivecontroleleyment shiftable from anrst position disengaged relative toanother drive control element to a second position of engagement withsaid other element andshiftable out of said second position whenoperation of said ignition system is momentarily 4interrupted to relievethe thrust load at said shiftable element, motion transmitting means forshifting said shiftable control element, actuating means operable uponsaid motion transmitting means for eiiecting shift of said shiftabledrive control element between its two said positions by saidfmotiontransmitting means, and circuit means including a pair of seriesarranged switches vfor controlling interruption of the ignition system,one of said switches being operablevby said motion transmitting meansand the other of said switches being operable by said actuating means.

.2. In a power transmission for driving a vehicle having an engineprovided with an ignition system; a shiftable transmission drive controlelement shiftable from a first position disengaged relative to anotherdrive control element to a Second position of engagement with said otherelement and shiftable out of 'said second position when operation ofsaid ignition system is momentarily interrupted to relieve the thrustload element, motion transmitting means for shifting said shiftablecontrol element, actuating means operable upon said motion transmittingmeans for effecting shift of 'said .shiftable drive control elementbetween its two .said positions by said motion transmitting means, andcircuit means including a pair of series arranged interrupter and aground applying switch for controlling the ignition system, one of saidswitches being operable by said motion transmitting means and the otherof said pair of switches being operable by said actuating means.

3. In a power transmission for driving a vehicle having an engineprovided with an ignition system; a shiftable transmission drive controlelement shiftable from a first position disengaged lrelative to anotherdrive control element -to a -second position of engagement with saidother .element and shiftable out of said second position when operationof said ignition system is momentarily interrupted to relieve the thrustload at said shiftable element, motion transmitting means for shiftingsaid shiftable control element, actuating means operable upon saidmotion transmitting means for effective shift of said shiftable drivecontrol element between its two said positions by said motiontransmitting means, and circuit means including a pair of seriesarranged switches for controlling interruption of the ignition system,one of said switches being a nomally closedswitch operable by saidmotion transmitting means and the other of said switches being anormally open switch operable by saidactuating means.

.4, In a power transmission for driving a vehicle having an enginev.provided with an ignition system; a vshiftable transmission drivecontrol element shiftable from a first position disengaged relative `toanother drive control element to a .second-position of engagement withsaid other element and shiftable out of said second position whenoperation of said ignition system is momentarily interrupted to relieve`the thrust load at -said shiftable element, motion transmitting meansfor shifting said shiftable control element, actuating -means operableupon said motion ytransmitting means for effecting shift of saidshiftable drive control element between its two said positions by saidmotion transmitting means, circuitmeans including a pair of seriesarranged switches for controlling interruption of the ignition system,one of said switches being a normally yclosed switch and the other avnormally open switch, switch operating means on said motiontransmitting means movable relative tosaidoneswitch for effectingconditioning thereof in open position when said shiftable drivecontrolelement is in said first position and for effecting Conditioningthereof in closed position when said shiftable element is in :saidsecond position, and switch operatingmeans on said actuating meansmovable relative to said other switch for effecting conditioning thereofin closed position when said rst switch is closed and for effectingvconditioning thereof in open position as an incident to disengagingmovementof said shiftable control element.

Y5. In a 4power transmission for driving a vehicle having an engineprovided with anignition system; a shiftable transmission drive controlelement shiftable from a first position disengaged relative to anotherdrive control element to a second position of engagement with said otherelement and shiftable out of said second position when operation of saidignition system is momentarily interrupted to relieve the thrust load atsaid shiftable element, motion transmitting means for shifting saidshiftable control element, actuating-means operable upon said motiontransmitting means for eifecting shift of said shiftable drive controlelement between its two said positions by said motion transmittingmeans, circuit means including a pair of series arranged switches forcontrolling interruption of the ignition system, one of saidswitchesbeing a normally closed switch and the other a normally openswitch, first switch operating means on said motion transmitting means,second switch operating means on said actuating means, said one switchand said first switch operating means being relatively mov- Vable foreffecting conditioning of said one switch in open position when saidshiftable drive control element is in said 'irst position and foreffecting conditioning thereof in closed position when said shiftableelement is in said second position, and said second switch and saidsecond operating means being relatively movable for effectingconditioning of said second switch in closed position as an incident tooperation of said actuatingr means for effecting shift of said shiftableelement out of said second position when said first switch is closed andfor effecting conditioning thereof in open position as an incident todisengaging movement of said shiftable control element.

6. In a power transmission for driving a vehicle having an engineprovided with an ignition system; a shiftable transmission drive controlelement shiftable from a first position disengaged relative to anotherdrive control element to a second position of engagement with said otherelement and shiftable out of said second position when operation of saidignition system is momentarily interrupted to relieve the thrust load atsaid shiftable element, motion transmitting means including a yokemember movable for shifting said shiftable control element, actuatingmeans including a differential pressure actuated piston operable uponsaid motion transmitting means for eiiecting shift of said shiftabledrive control element between its two said positions by said motiontransmitting means, and circuit means including a pair of seriesarranged switches for controlling interruption of the ignition system,one of said switches being operable by said yoke member, and the otherof said pair of switches being operable by said piston.

7. In a power transmission for driving a vehicle having an engineprovided with an ignition system; a shiftable transmission drive controlelement shiftable from a rst position disengaged relative to anotherdrive control element to a second position of engagement with said otherelement and shiftable out of said second position when operation of saidignition system is momentarily interrupted to relieve the thrust load atsaid shiftable element, motion transmitting means including a yokemember movable for shifting said shiftable control element, actuatingmeans including a diierential pressure actuated piston operable uponsaid motion transmitting means for effecting shift of said shiftabledrive control element between its two said positions by said motiontransmitting, means, circuit means including a pair of series arrangedswitches for controlling interruption of the ignition system, adjustablecam means on said yoke for operating one of said switches, cam means onsaid piston for operating the other of said pair of switches.

8. In a power transmission for driving Ya vehicle having an engineprovided with an ignition system; a shiftable transmission drive controlelement shiftable from a rst position disengaged relative to anotherdrive control element-to a second position of engagement with said otherelement and shiftable out of said second position when operation of saidignition system is momentarily interrupted to relieve the thrust load atsaid shiftable element, motion transmitting means including a yokemember movable for shifting said shiftable control element, actuatingmeans Cil 16 including a differential pressure actuated piston operableupon said motion transmitting means for eifecting shift of saidshiftable drive control element between its two said positions by saidmotion transmitting means, circuit means including a pair of seriesarranged switches for controlling interruption of the ignition system,one of said switches being a normally closed switch and the other beinga normally open switch, abutment means carried by said yoke and movabletherewith for operating said one switch, said abutment meansconditioning said one switch in open condition in its positioncorresponding to said iirst position of said shiftable control elementand in substantially all other positions thereof excepting thatcorresponding to said second position of said shiftable control element,and cam means carried by said piston for momentarily operating saidother switch from its open to its closed position during movement ofsaid piston for effecting shift of said shiftable control elementbetween said first and second positions and during at least a part ofthat movement of said piston for eiiecting shift of said shiftablecontrol element between said second and rst positions corresponding tomovement of said yoke abutment between closed and open positions of saidone switch.

9. In a power transmission for driving a vehicle having an engineprovided with an ignition system; a shiftable transmission drive controlelement shiftable from a first position disengaged relative to anotherdrive control element to a second position of engagement with said otherelement and shiftable out of said second position when operationY ofsaidV ignition system is momentarily interrupted to relieve the thrustload at said shiftable element, motion transmitting means including ayoke member movable for shifting said shiftable control element,actuating means including a differential pressure actuated pistonoperable upon said motion transmitting means for effecting shift of saidshiftable drive control element between its two said positions by saidmotion transmitting means, circuit means including an igintion primarycoil, an ignition interrupting switch, a control switch for saidinterrupting switch, a solenoid controlled valve for controllingactuation of said piston, a speed responsive ground switch and anaccelerator operable ground switch, said control switch being a normallyclosed switch and said other switches being normally open, means carriedby said yoke member for operating 'said control switch to open the samewhen effecting engagement of said drive control elements butfacilitating closing of said control switch when effecting disengagementof said drive control elements such that said control switch is closedwhenever said drive control elements are disengaged, and cam means onsaid piston operable during operation of said piston for effectingdisengagement of said shiftable drive control element and only when saidcontrol switch and one of said governor or accelerator switches areclosed, for closing said interrupter switch to apply a ground to saidprimary coil to interrupt the ignition and facilitate disengagement ofsaid drive control elements.

LOUIS B. FORMAN.

No references cited.

